1. Field of the Invention
The present invention relates to 3-(unsubstituted or substituted benzyl)-1-alkyl-2-oxocyclopentane carboxylic acid alkyl ester derivatives, a method for the preparation of the same, a fungicide containing the same, and a use thereof as intermediate compounds.
2. Description of the Related Art
EP-A-294,222 (the Japanese counterpart being Japanese Patent Laid-open Publication (kokai) No. 79,117/1989), U.S. Pat. No. 4,938,792 (the Japanese counterpart being Japanese Patent Laid-open Publication (kokai) No. 93,574/1989 and the European counterpart being EP-A-267,778), and EP-A-341,954 (the Japanese counterpart being Japanese Patent Laid-open Publication (kokai) No. 42,003/1990) disclose a 2-(unsubstituted or substituted benzyl)-5-alkylcyclopentanone derivative as represented by the general formula (VII): ##STR2## where R.sup.1 is a lower alkyl group; X is a halogen atom, a cyano group, an alkyl group, a haloalkyl group or a nitro group; and
m is 0 or an integer of 1 to 5 and when m is greater than 1 each X can be the same or different, PA1 X' is a halogen atom, a C.sub.1 -C.sub.5 alkyl group or a phenyl group; and n is 0, 1 or 2. PA1 Z.sup.1' and Z.sup.2' are each a halogen atom; and PA1 R.sup.1', X' and n have the same meaning as above. PA1 R.sup.1, R.sup.2, X and m have the same meaning as above. PA1 X is a halogen atom, a cyano group, an alkyl group, a haloalkyl group, a phenyl group or a nitro group; and PA1 m is 0 or an integer from 1 to 5 and when m is greater than 1 each X can be the same or different. PA1 X is a halogen atom, a cyano group, an alkyl group, a haloalkyl group, a phenyl group or a nitro group; and PA1 m is 0 or an integer from 1 to 5 and when m is greater than 1 each X can be the same or different. PA1 R.sup.1, R.sup.2, X, and m have the same meaning as above.
which can be employed as intermediate compounds for pesticides, medicine, and the like.
U.S. Pat. No. 4,938,792 (Japanese Patent Laid-open Publication (kokai) No. 93,574/1989 and the European counterpart being Japanese Patent Laid-open Publication (kokai) No. 42,003/1990) contains a detailed description of reaction schemes (i) and (ii), as will be described hereinafter, for the preparation of a 2-(unsubstituted or substituted benzyl)-5-alkylcyclopentanone derivative as represented by the general formula (VII'): ##STR3## where R.sup.1 is a C.sub.1 -C.sub.5 alkyl group;
The reaction scheme (i) for the preparation of the 2-(unsubstituted or substituted benzyl)-5-alkylcyclopentanone derivative as represented by the general formula (VII') involves benzylating a 2-oxocyclopentane carboxylic acid alkyl ester derivative as will be represented by the general formula (II') with an unsubstituted or substituted benzyl halide as will be represented by the general formula (III'); alkylating the resulting 1-(unsubstituted or substituted benzyl)-2-oxocyclopentane carboxylic acid alkyl ester derivative as will be represented by the general formula (IV') with an alkyl halide; hydrolyzing the ester group of the resulting 3-alkyl-1-(unsubstituted or substituted benzyl)-2-oxocyclopentane carboxylic acid alkyl ester derivative as will be represented by the general formula (VIII); and decarboxylating the resulting compound, thereby giving the 2-(unsubstituted or substituted benzyl)-5-alkylcyclopentanone derivative as represented by the general formula (VII'). ##STR4## where R.sup.2' is a C.sub.1 -C.sub.3 alkyl group;
The reaction scheme (ii) for the preparation of the 2-(unsubstituted or substituted benzyl)-5-alkylcyclopentanone derivative as represented by the general formula (VII') involves benzylating a 3-alkyl-2-oxocyclopentane carboxylic acid alkyl ester derivative as will be represented by the general formula (IX) with the unsubstituted or substituted benzyl halide as represented by the general formula (III'); hydrolyzing the ester group of the resulting 3-alkyl-1-(unsubstituted or substituted benzyl)-2-oxocyclopentane carboxylic acid alkyl ester derivative as represented by the general formula (VIII); and decarboxylating the resulting compound, thereby giving the compound as represented by the general formula (VII'). ##STR5## where R.sup.1', R.sup.2', X', Z.sup.2' and n have the same meaning as above.
In order to provide good yield in the method as indicated in the reaction schemes as have been described hereinabove, the alkylation in the reaction scheme (i) should be carried out by using a strong base such as sodium hydride or the like in an aprotic solvent; and the reaction in the reaction scheme (ii) should be carried out in a reaction scheme, as will be described hereinafter, by alkylating a 2-oxocyclopentane carboxylic acid alkyl ester derivative as will be represented by the general formula (II') with the alkyl halide as represented by the general formula (VI') in the presence of a base; subjecting the resulting 1-alkyl-2-oxocyclopentane carboxylic acid alkyl ester derivative as will be represented by the general formula (X) to rearrangement in a lower alcohol in the presence of an alkali metal lower alkoxide; and isolating the resulting 3-alkyl-2-oxocyclopentane carboxylic acid alkyl ester derivative as represented by the general formula (IX): ##STR6## where R.sup.1', R.sup.2', and Z.sup.1' have the same meaning as above.
In order to provide precursors of the 2-(unsubstituted or substituted benzyl)-5-alkylcyclopentanone derivatives as represented by the general formula (VII') and the 3-alkyl-1-(unsubstituted or substituted benzyl)-2-oxocyclopentane carboxylic acid alkyl ester derivatives as represented by the general formula (VIII) with high yield, a strong base such as sodium hydride and the like should be employed or the intermediate compounds should be isolated and purified from the reaction scheme.
Particular care should be required, however, in using sodium hydride in a large quantity because hydrogen is caused to occur during the reaction of the sodium hydride. Further, the isolation and the purification of the intermediate compounds require a post-treatment step in the reaction so that it suffers from the disadvantage in terms of preparation because the reaction step is increased.
Hence, strong demands have been made to provide a method in which the yield of the product is not reduced, a which is easily and readily handled can be employed, and the isolation and purification of the intermediate compound are not required to thereby reduce the reaction steps.